Projectile



Aug. 1, 1961 R. M. BLEAKNEY PRQJECTILE Filed June 50, 1944 l lllI/I S2,994,273 PROJECTILE Robert M. Bleakney, Albuquerque, N. Mex., assignor,by mesne assignments, to the United States of America as represented bythe Secretary of the Navy Filed June '30, 1944, Ser. No; 543,001 6Claims. (Cl. 10293) This invention relates to projectiles, and moreparticularly to sub-caliber sabot projectiles.

An object of this invention is to provide a sabot projectile comprisinga sub-caliber core having a pair of releasable elements of substantiallyfull caliber dimension mounted near the nose and near the rear of thecore, respectively, for supporting and centering the core in a gunbarrel, and a releasable light-weight spacer surrounding the core formaintaining the supporting and centering elements in spaced relation.

Another object of this invention is to provide a sabot projectile asdescribed above in which the spacer also afiords lateral support to thesupporting and centering elements.

Still another object is to provide a sabot projectile of the characterdescribed in which the spacer is partially segmented radially so as todisintegrate readily after the projectile leaves the gun barrel.Preferably, the supporting and centering elements also have weakenedzones which cause them to disintegrate readily after leaving the gunbarrel, under the influence of the centrifugal force set up by rotationof the projectile.

A further object of the invention resides in the provision of a sabotprojectile comprising a sub-caliber core having a substantially fullcaliber discardable sabot, a substantially full caliber metal ringforming a bourrelet near the nose of the core, and a light-weightsub-caliber sleeve of plastic, fiber, or the like, surrounding the corebetween the sabot and the ring for supporting the ring latterally andmaintaining it in spaced relation to the sa ot.

Another object of the invention is to provide a projectile as describedabove which is positive in operation and easy to manufacture andassemble, being adapted to large quantity production.

These and other objects of the invention will be obvious from thefollowing specification and the accompanying drawing, in which:

FIG. 1 is a longitudinal sectional view, partly in elevation, showingthe new projectile in a gun barrel; FIFIG. 2 is a front elevation of theprojectile shown in FIG. 3 is a view similar to FIG. form of thebourrelet ring;

FIG. 4 is a cross-sectional view on line 4-4 of FIG. 1;

FIG. 5 is a view similar to FIG. 4 showing a modified form of thespacing element; and

FIG. 6 is a cross-sectional view taken on line 66 of FIG. 1.

The projectile comprises a sub-caliber steel core 10 having an ogivenose portion 10a. Near the ogive, a full caliber ring-shaped bourrelet11 is mechanically connected with the core by means of threads 12 orother suitable means, such as a press fit. The ring is made of steel andis partially segmented by cutaway portions 13 of generally circular formextending to the inner edge of the ring, and by radial cuts 14 whichextend outwardly from the cutaway portions 13 to within a short distanceof the outer periphery of the ring. Thus, the recesses 13 and cuts 14partially divide the ring into segments held together by weakened outerportions 13a, the widths of which are determined by the breakingstrength of the material and by the dimensions and speed of rotation ofthe projectile, it being understood that the ring is adapt- 2 showing amodified ed to break apart at the weakened portions 13a undercentrifugal force when the rotating projectile emerges from the gunbarrel, as will be described in greater detail presently.

A modified form of the bourrelet ring is shown in FIG. 3. As thereshown, the ring 11a has recesses .15 which do not extend into the inneredge of the ring, as do the cutaway portions shown in FIG. 2. Radialcuts 14a extend inwardly and outwardly from the recesses 15 leavingouter uncut portions 15a. The cutaway portions 13 and the recesses 15serve both to lighten the weight of the ring and to weaken the ring sothat it will break apart readily under centrifugal force on leaving thegun barrel.

To the rear of the ring 11, a partially segmented spacer 16 is mountedon the core, the spacer being of sleevelike form and made oflight-weight material, such as wood, plastic, or the like. The spacerhas radial cuts 17 extending outwardly from its inner surface, leavinguncut portions 18 adjacent its outer periphery, the radial dimension ofthe uncut portions being determined by the breaking strength of thematerial and by the dimensions and speed of rotation of the projectile.

In FIG. 5, I have shown a modified form of the spacer in which thesleeve 16a has radial cuts 17a extending inwardly from the outerperiphery of the ring, leaving uncut portions 18a adjacent the innersurface of the ring. The spacers 16, 16a are somewhat smaller inexternal diameter than the adjacent bourrelet ring 11.

The front end of the spacer 16 bears against the ring 11 while the rearend of the spacer bears against the front surface 21 of a sturdy fullcaliber steel sabot 19 fitted closely in an annular groove 20 by whichit is well supported near the base of the core 10. The bourrelet ring 11is driven firmly against the spacer 16, producing what may convenientlybe termed an initially taut sub-caliber projectile. In other words, noneof the components is loosely emplaced on the sub-caliber core 10. Thesabot 19 is completely segmented radially and the segments are held inposition in groove 20 by a turning band 22 of copper or other suitablematerial which is pressed or otherwise mounted on the sabot, the bandhaving inwardly extending annular tongues 22a disposed in correspondingannular grooves in the periphery of the sabot. By thus mounting theturning band on the sabot, the band is prevented from being strippedfrom the sabot when the projectile is fired from the gun. A sealing disk23, which may be made of copper, brass, or the like, is mounted on thebase of the core and engages the rear face of the sabot so as to preventthe high pressure powder gases from leaking through the radial cuts inthe sabot with a consequent loss of projectile velocity.

When the projectile is fired from a gun, the turning band 22 is engravedby the rifling in the gun bore and imparts rotation to the core throughthe sabot on which the band is mounted and through the spacer 16 andring 11. As long as the projectile is in the gun barrel, the supportingand centering means comprising the ring 11 and the sabot 19 insure thatthe core is'axially centered in the barrel, this centering beingnecessary if the core is to be stable in flight after leaving thebarrel. When the projecticle emerges from the gun barrel, the ring,spacer, sabot, and turning band are released from the core in order todecrease the air resistance on the projectile and permit higher velocityin flight. This release is accomplished by breaking of the bourreletring and the spacer at their weakened zones and by rupture of therotating band, under the centrifugal force set up by the high speedrotation of the projectile. Thus, the projectile has the advantage of alarge base area against which the propellant gases act, combined withthe decreased weight and aerodynamic drag of the small caliber 3 core ascompared with a full caliber projectile, which permits higher corevelocity.

The spacer 16 supports the bourrelet ring 11 at its back, which ring isnot strongly mounted on the core, by transmitting the thrust imparted tothe ring by its contact with the bore of the gun, to the sabot which iswell supported on the core in the groove 20. This permits the use of arelatively thin bourrelet ring .11, resulting in a saving in weight anda decrease in the hearing surface in contact with the gun bore.

It will be apparent that the new projectile is of simple construction,has relatively few parts, and may be easily assembled. The threads 12are in such a direction that the bourrelet ring is driven backwardly andtightened against the spacer 16 by the rotation imparted to the corethrough the turning band. By thus tightening the bourrelet ring againstthe spacer 16, the sabot 19 may be prestressed laterally by the spacerso that the sabot is better adapted to withstand the turning or bendingforward moments exerted on its segments by the powder pressure. Also,because of the wedging action imposed upon the spacer by the bourreletring and the sabot, the spacer and bourrelet ring are adapted totransmit torque from the turning band and sabot to the core.

In accordance withthe present invention, I have provided a sub-calibersabot type projectile which is well supported and centered in the gunbarrel and which discards the supporting and centering means immediatelyupon leaving the gun barrel, whereby the sub-caliber core may proceedtoward the target at a high velocity and with potentially high strikingpower. It is to be understood that many possible embodiments of theinvention may be made, and the matter described and illustrated hereinis to be interpreted as illustrative and not in a limiting sense.

I claim:

1. An initially taut sub-caliber projectile comprising a sub-calibercore, a sabot, means securely mounting said sabot on the rear endportion of the core, a full caliber metal ring having a screw threadconnection with the core in front of the sabot, and an annular spacer ofrelatively light-weight material mounted on and extending around thecore against which spacer the ring is tightened by the screw threadconnection due to rotation of the core on acceleration, therebytransmitting a thrust to one side of the sabot in opposition to thepowder pressure against the other ,side of the sabot.

2. A sub-caliber projectile comprising a sub-caliber core having agroove, a sabot mounted in the groove and having a turning band, aspacer extending around the core abutting the sabot, a full caliber ringabutting the spacer, and a thread course mechanically connecting thering with the core, being of such direction that rotation imparted tothe core by the turning band tightens the ring against the spacer with awedging action to force the spacer against the sabot.

3. A sub-caliber projectile comprising a segmented sabot, asub-caliber'core, which is grooved to receive the segments and retainthe sabot, a full caliber ring which is thin relatively to the sabot,being mounted on the core in front of the sabot and having configuratedopenings extending endwise through the ring and spaced around the ringto reduce the weight thereof and provide weakened zones in the ring, athread course connecting the ring with the core, and a spacer extendingaround the core between the ring and the sabot for supporting said ringat its back and at a predetermined distance from the sabot. l

4. A sabot projectile comprising a sub-caliber core having an annulargroove in its rear end portion and a thread course in front of thegroove, a plurality of segments mounted in the groove and projectingradially from the core a substantial distance to form a sabot, a spacermounted on the core between the groove and said course, and a fullcaliber ring threaded on said course and screwed against the spacer toforce the same against the sabot segments, the ring, spacer and sabotbeing releasable from the core during flight of the projectile.

5. A sabot projectile comprising a sub-caliber core having an annulargroove in its rear end portion and a thread course in front of thegroove, a plurality of segments mounted in the groove and projectingradially from the core a substantial distance to form a sabot, a turningband mounted on the sabot for holding the segments together in saidgroove, a spacer mounted on the core between the groove and said courseand engageable with the front end of the turning band, and a fullcaliber ring threaded on said course and screwed against the spacer toforce the same against the sabot segments and said band, the ring,spacer and sabot being releasable from the core during flight of theprojectile.

6. A sabot projectile comprising a sub-caliber core having an annulargroove in its rear end portion and a thread course in front of thegroove, a plurality of segments mounted in the groove and projectingradially from the core a substantial distance to form'a sabot, asegmented spacer mounted on the core between the groove and said course,a full caliber segmented ring threaded on said course and screwedagainst the spacer to force the same against the sabot segments, thering, spacer and sabot being releasable from the core during flight ofthe projectile, and a sealing disc on the core engaging the rear end ofthe sabot to resist the passage of high pressure gas between saidsegments.

References Cited in the file of this patent UNITED STATES PATENTS 36,773Emry Oct. 28, 1862 132,903 Dana Nov. 12, 1872 FOREIGN PATENTS 131,034Great Britain Aug. 21, 1919 46,057 Sweden 'Nov. 5, 1919 809,845 FranceDec. 19, 1936

